1 files changed, 102 insertions, 0 deletions
diff --git a/src/lib/Counter.svelte b/src/lib/Counter.svelte
new file mode 100644
index 0000000..0df76f5
--- /dev/null
+++ b/src/lib/Counter.svelte
@@ -0,0 +1,102 @@
+<script lang="ts">
+	import { spring } from 'svelte/motion';
+
+	let count = 0;
+
+	const displayed_count = spring();
+	$: displayed_count.set(count);
+	$: offset = modulo($displayed_count, 1);
+
+	function modulo(n: number, m: number) {
+		// handle negative numbers
+		return ((n % m) + m) % m;
+	}
+</script>
+
+<div class="counter">
+	<button on:click={() => (count -= 1)} aria-label="Decrease the counter by one">
+		<svg aria-hidden="true" viewBox="0 0 1 1">
+			<path d="M0,0.5 L1,0.5" />
+		</svg>
+	</button>
+
+	<div class="counter-viewport">
+		<div class="counter-digits" style="transform: translate(0, {100 * offset}%)">
+			<strong class="hidden" aria-hidden="true">{Math.floor($displayed_count + 1)}</strong>
+			<strong>{Math.floor($displayed_count)}</strong>
+		</div>
+	</div>
+
+	<button on:click={() => (count += 1)} aria-label="Increase the counter by one">
+		<svg aria-hidden="true" viewBox="0 0 1 1">
+			<path d="M0,0.5 L1,0.5 M0.5,0 L0.5,1" />
+		</svg>
+	</button>
+</div>
+
+<style>
+	.counter {
+		display: flex;
+		border-top: 1px solid rgba(0, 0, 0, 0.1);
+		border-bottom: 1px solid rgba(0, 0, 0, 0.1);
+		margin: 1rem 0;
+	}
+
+	.counter button {
+		width: 2em;
+		padding: 0;
+		display: flex;
+		align-items: center;
+		justify-content: center;
+		border: 0;
+		background-color: transparent;
+		color: var(--text-color);
+		font-size: 2rem;
+	}
+
+	.counter button:hover {
+		background-color: var(--secondary-color);
+	}
+
+	svg {
+		width: 25%;
+		height: 25%;
+	}
+
+	path {
+		vector-effect: non-scaling-stroke;
+		stroke-width: 2px;
+		stroke: var(--text-color);
+	}
+
+	.counter-viewport {
+		width: 8em;
+		height: 4em;
+		overflow: hidden;
+		text-align: center;
+		position: relative;
+	}
+
+	.counter-viewport strong {
+		position: absolute;
+		display: flex;
+		width: 100%;
+		height: 100%;
+		font-weight: 400;
+		color: var(--accent-color);
+		font-size: 4rem;
+		align-items: center;
+		justify-content: center;
+	}
+
+	.counter-digits {
+		position: absolute;
+		width: 100%;
+		height: 100%;
+	}
+
+	.hidden {
+		top: -100%;
+		user-select: none;
+	}
+</style>